| 1. |
- He, Youjun, et al.
(författare)
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Poly(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b ]dithiophene vinylene): Synthesis, Optical and Photovoltaic Properties
- 2010
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Ingår i: JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY. - : John Wiley and Sons, Ltd. - 0887-624X .- 1099-0518. ; 48:8, s. 1822-1829
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Tidskriftsartikel (refereegranskat)abstract
- A new benzodithiophene (BDT)-based polymer, poly(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b]dithiophene vinylene) (PBDTV), was synthesized by Pd-catalyzed Stille-coupling method. The polymer is soluble in common organic solvents and possesses high thermal stability. PBDTV film shows a broad absorption band covering from 350 nm to 618 nm, strong photoluminescence peaked at 545 nm and high hole mobility of 4.84 x 10(-3) cm(2)/Vs. Photovoltaic properties of PBDTV were studied by fabricating the polymer solar cells based on PBDTV as donor and PC70BM as acceptor. With the weight ratio of PBDTV: PC70BM of 1:4 and the active layer thickness of 65 nm, the power conversion efficiency of the device reached 2.63% with V-oc = 0.71 V, I-sc = 6.46 mA/cm(2), and FF = 0.57 under the illumination of AM1.5, 100 mW/cm(2).
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| 2. |
- Qian, Deping, et al.
(författare)
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Correlating the Hybridization of Local-Exciton and Charge-Transfer States with Charge Generation in Organic Solar Cells
- 2023
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- In organic solar cells with very small energetic-offset (& UDelta;ELE - CT), the charge-transfer (CT) and local-exciton (LE) states strongly interact via electronic hybridization and thermal population effects, suppressing the non-radiative recombination. Here, we investigated the impact of these effects on charge generation and recombination. In the blends of PTO2:C8IC and PTO2:Y6 with very small, ultra-fast CT state formation was observed, and assigned to direct photoexcitation resulting from strong hybridization of the LE and CT states (i.e., LE-CT intermixed states). These states in turn accelerate the recombination of both CT and charge separated (CS) states. Moreover, they can be significantly weakened by an external-electric field, which enhanced the yield of CT and CS states but attenuated the emission of the device. This study highlights that excessive LE-CT hybridization due to very low , whilst enabling direct and ultrafast charge transfer and increasing the proportion of radiative versus non-radiative recombination rates, comes at the expense of accelerating recombination losses competing with exciton-to-charge conversion process, resulting in a loss of photocurrent generation.
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| 3. |
- Yan, Xin, et al.
(författare)
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Highly efficient ternary solar cells with reduced non-radiative energy loss and enhanced stability via two compatible non-fullerene acceptors
- 2022
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 10:29, s. 15605-15613
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Tidskriftsartikel (refereegranskat)abstract
- A ternary strategy by introducing a third component into a binary host system has been proven to be a simple and promising method to boost the power conversion efficiency (PCE) and stability of organic solar cells (OSCs). Herein, a high efficient ternary OSC is fabricated, wherein, a non-fullerene acceptor, namely MOIT-M, is introduced as a third component into the PM6:BTP-eC9 blend. MOIT-M possesses good complementary absorption spectra and aligned cascade energy levels with the host binary blend, which benefits light harvesting, exciton dissociation, and charge transport. Moreover, MOIT-M exhibits good miscibility with BTP-eC9, forming a well-mixed phase, which improves molecular packing for better charge transport and optimizes ternary blend morphology. Notably, the incorporation of MOIT-M suppresses non-radiative recombination, leading to reduced non-radiative energy losses (Delta E-nr). As a result, the ternary OSC exhibits a significantly increased PCE of 18.5% with a lower Delta E-nr of 0.21 eV in comparison with the control binary PM6:BTP-eC9 device with a PCE of 17.4% and a Delta E-nr of 0.24 eV. In addition, the ternary OSC displays better storage stability compared to the PM6:BTP-eC9 system. This work indicates that a ternary strategy via combining two compatible small molecule acceptors is effective to simultaneously improve the efficiency and stability of OSCs.
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| 4. |
- Zhang, Zhiliang, et al.
(författare)
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Enhancing intermolecular packing and light harvesting through asymmetric non-fullerene acceptors for achieving 18.7% efficiency ternary organic solar cells
- 2023
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 11:28, s. 15553-15560
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the ternary strategy has been proven to be an effective way to improve the performance of organic solar cells (OSCs). Herein, an asymmetric medium-band gap non-fullerene acceptor (AFIC) is synthesized and added as the third component into the PM6:BTP-eC9 binary blend for a highly efficient ternary OSC. AFIC exhibits a well-complementary absorption spectrum with the host binary blend, which benefits light harvesting of the active layer. Furthermore, AFIC shows a large dipole moment and good miscibility with BTP-eC9, which facilitates the formation of a stable well-mixed phase and enhances molecular packing in the blend, leading to improved charge transport and suppressed charge recombination in ternary devices. As a result, the ternary OSC based on PM6:BTP-eC9:AFIC demonstrates a significantly improved power conversion efficiency (PCE) of 18.7% while the binary OSC based on PM6:BTP-eC9 shows a PCE of 17.5%, which is attributed to the synergistic enhancement of the open-circuit voltage (V-oc), short-circuit current density (J(sc)), and fill factor (FF).
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| 5. |
- Fan, Qunping, 1989, et al.
(författare)
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A Non-Conjugated Polymer Acceptor for Efficient and Thermally Stable All-Polymer Solar Cells
- 2020
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Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 59:45, s. 19835-19840
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Tidskriftsartikel (refereegranskat)abstract
- A non-conjugated polymer acceptor PF1-TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient >105 cm−1, a high LUMO level of −3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1-TS4-based all-PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is ≈45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1-TS4-based all-PSC has good thermal stability with ≈70 % of its initial PCE retained after being stored at 85 °C for 180 h, while the IDIC16-based device only retained ≈50 % of its initial PCE when stored at 85 °C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non-conjugated thioalkyl segments.
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| 6. |
- Lin, Yuze, et al.
(författare)
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Mapping Polymer Donors toward High-Efficiency Fullerene Free Organic Solar Cells
- 2017
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 29:3
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Tidskriftsartikel (refereegranskat)abstract
- Five polymer donors with distinct chemical structures and different electronic properties are surveyed in a planar and narrow-bandgap fused-ring electron acceptor (IDIC)-based organic solar cells, which exhibit power conversion efficiencies of up to 11%.
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| 7. |
- Liu, Tao, et al.
(författare)
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16% efficiency all-polymer organic solar cells enabled by a finely tuned morphology via the design of ternary blend
- 2021
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Ingår i: Joule. - : CELL PRESS. - 2542-4351. ; 5:4, s. 914-930
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Tidskriftsartikel (refereegranskat)abstract
- A SUMMARY There is an urgent demand for all-polymer organic solar cells (AP-OSCs) to gain higher efficiency. Here, we successfully improve the performance to 16.09% by introducing a small amount of BN-T, a B <- N-type polymer acceptor, into the PM6:PY-IT blend. It has been found that BN-T makes the active layer, based on the PM6:PY-IT:BN-T ternary blend, more crystalline but meanwhile slightly reduces the phase separation, leading to enhancement of both exciton harvesting and charge transport. From a thermodynamic viewpoint, BN-T prefers to reside between PM6 and PY-IT, and the fraction of this fine-tunes the morphology. Besides, a significantly reduced nonradiative energy loss occurs in the ternary blend, along with the coexistence of energy and charge transfer between the two acceptors. The progressive performance facilitated by these improved properties demonstrates that AP-OSCs can possibly comparably efficient with those based on small molecule acceptors, further enhancing the competitiveness of this device type.
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| 8. |
- Yang, Ding, et al.
(författare)
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High-performance semitransparent organic solar cells enabled by pseudo-planar heterojunction structures combined with optical engineering
- 2022
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 10:39, s. 14597-14604
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Tidskriftsartikel (refereegranskat)abstract
- Semitransparent organic solar cells (ST-OSCs) are emerging as a promising renewable energy technology for building integration. However, how to solve the trade-off between power-conversion efficiency (PCE) and average visible transmittance (AVT) is always the key point for the further development of ST-OSCs. Herein, a pseudo-planar heterojunction (PPHJ) active layer, by sequentially depositing a polymer donor layer (PM6) and a small-molecule acceptor layer (BTP-eC9), was employed to improve the device performance and AVT, resulting in PCEs of 18.5% for opaque devices and 13.3% for semitransparent OSCs with an AVT of 18.5%. Furthermore, by introducing an effective anti-reflective covering layer, the AVT of the ST-OSCs was further improved up to 27.8% with little minus effect on the PCE (13.1%), as well as an impressive light-utilization efficiency (LUE) of 3.64% and a color-rendering index (CRI) of 94.6. It is worth noting that the PCE of 13.1% is the highest value at an AVT of over 25%. Our strategy represents a unique approach for improving the AVT and PCE of ST-OSCs simultaneously, facilitating the commercial development of OSCs.
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| 9. |
- Chen, Xian-Kai, et al.
(författare)
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A unified description of non-radiative voltage losses in organic solar cells
- 2021
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Ingår i: Nature Energy. - : Springer Nature. - 2058-7546. ; 6:8, s. 799-806
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Tidskriftsartikel (refereegranskat)abstract
- Organic solar cells based on non-fullerene acceptors have enabled high efficiencies yet their charge dynamics and its impact on the photovoltaic parameters are not fully understood. Now, Chen et al. provide a general description of non-radiative voltage losses in both fullerene and non-fullerene solar cells. Recent advances in organic solar cells based on non-fullerene acceptors (NFAs) come with reduced non-radiative voltage losses (Delta V-nr). Here we show that, in contrast to the energy-gap-law dependence observed in conventional donor:fullerene blends, the Delta V-nr values in state-of-the-art donor:NFA organic solar cells show no correlation with the energies of charge-transfer electronic states at donor:acceptor interfaces. By combining temperature-dependent electroluminescence experiments and dynamic vibronic simulations, we provide a unified description of Delta V-nr for both fullerene- and NFA-based devices. We highlight the critical role that the thermal population of local exciton states plays in low-Delta V-nr systems. An important finding is that the photoluminescence yield of the pristine materials defines the lower limit of Delta V-nr. We also demonstrate that the reduction in Delta V-nr (for example, <0.2 V) can be obtained without sacrificing charge generation efficiency. Our work suggests designing donor and acceptor materials with high luminescence efficiency and complementary optical absorption bands extending into the near-infrared region.
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| 10. |
- Fan, Qunping, 1989, et al.
(författare)
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Fluorinated Photovoltaic Materials for High-Performance Organic Solar Cells
- 2019
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Ingår i: Chemistry - An Asian Journal. - : Wiley. - 1861-471X .- 1861-4728. ; 14:18, s. 3085-3095
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Forskningsöversikt (refereegranskat)abstract
- Over the past decade, organic solar cells (OSCs) have achieved a dramatic boost in their power conversion efficiencies from about 6 % to over 16 %. In addition to developments in device engineering, innovative photovoltaic materials, especially fluorinated donors and acceptors, have become the dominant factor for improved device performance. This minireview highlights fluorinated photovoltaic materials that enable efficient OSCs. Impressive OSCs have been obtained by developing some important molds of fluorinated donor and acceptor systems. The molecular design strategy and the matching principle of fluorinated donors and acceptors in OSCs are discussed. Finally, a concise summary and outlook are presented for advances in fluorinated materials to realize the practical application of OSCs.
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